<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>在元素周围画线</title>
    <style>
        p{
            border: 1px solid red;
            outline: green dotted thick;
        }
    </style>
</head>
<body>
    <p><b>注意:</b> 如果只有一个 !DOCTYP E指定 IE8 支持 outline 属性。</p> 
</body>
</html>